I am going through the same thing and I read how the body has more hormones in the body due to being pregnant and when you miscarry your body has to bet back on track but in the mean time you are more fertile. Doctors will tell you to wait so you can have a regular cycle and if you get pregnant they can track approximate time you got pregnant but like you I would really like to get pregnant right away. I wasn't that far along but me and my husband were devastated that the pregnancy didn't last as soon as I found out I was pregnant is when I lost the baby. I am still bleeding and I am not planning to get pregnant right away but will leave it up in the air and then the next month we will start tracking my ovulation and actual try but if it happens this month we will be very happy. Best of luck to you and I hope things work out for you. Oh and folic acid is very important and so is prenatal vitamins so you want to continue to take them now before you even get pregnant again.
I don't know a % for getting pregnant after a m/c, I do know that everyone is different & it takes some women longer to get their cycle back on track. Some of us are lucky & our cycle picks right up. I had my m/c on the 2nd & I ovulated 2 weeks later like normal. Folic acid doesn't necessarily help to get pregnant but it does help with the risks of birth defects.